GaN-based semiconductor devices for power electronics or a high-frequency switching devices has been in development. However, GaN-based semiconductor devices have some drawbacks relating to electrical characteristics thereof even though in general GaN-based devices can have higher breakdown voltages and lower resistance.
For example, “current collapse” is one of the possible drawbacks relating to the electrical characteristics of the GaN-based semiconductor device. “Current collapse” refers to a phenomenon where when a drain voltage is applied to a transistor after previously applying a high drain voltage to the transistor, the ON-state resistance of the transistor rises. One of the causes of the current collapse is considered to be that channel electrons are trapped by a surface of a GaN-based semiconductor or the like.